2200 Military Time

2200 is 10:00 PM, ten o’clock in the night. On a 24-hour clock with a colon it is 22:00; in military style the colon goes and the four digits stand alone. The hour is 22 hours after midnight and 2 hours before the next one.

Ten in the evening, the start of the night differential in many pay systems and of quiet hours in most units.

To read it, look at the first two digits: the hour is above 12, so subtract 12 and add PM: 22 − 12 = 10. The last two digits are minutes and never change, so 2225 is 10:25 PM and 2250 is 10:50 PM.

Military to 12-hour. Split the four digits into hours and minutes, the hour is above 12, so subtract 12 and add PM: 22 − 12 = 10. So 2215 becomes 10:15 PM and 2245 becomes 10:45 PM.

12-hour to military. 10 PM is a PM hour, so add 12: 10 + 12 = 22. 10:05 PM is 2205. Drop the colon and the AM or PM, and you have the four digits.

The mistakes worth knowing: “22:00 PM” is a mix of both systems and means nothing, because a 24-hour time already says which half of the day it is. And 2200 is not 22:00 AM; there is no 22 o’clock in the morning.

2200 is said “twenty-two hundred”. The “hundred” stands in for the two zeros; nobody says “thirteen zero zero”. Numbers from ten upward are said as ordinary numbers: “twenty-two hundred”, not “one two hundred”.

Minutes follow the same logic. 2205 is “twenty-two zero five” and 2240 is “twenty-two forty”. Single-digit minutes get a spoken zero, so the listener knows a digit is there.

About the word “hours”: in speech, “twenty-two hundred hours” is everywhere, and nobody will correct you. In writing, Army Regulation 25-50 says the word is not used with military time, so a memorandum reads “at 2200”, not “at 2200 hours”.

On its own, 2200 is local time wherever it is written. When the four digits carry a letter, the letter is the time zone. Z stands for Zulu, which is UTC, and J (Juliet) means the local time of the person speaking. The table converts 2200Z to the four US zones, in standard time and in daylight saving time.

Eastern Time is four hours behind UTC from March to November and five hours behind the rest of the year, which is why one Zulu time maps to two possible local times. The other three zones follow the same pattern an hour further west each.

Midnight has a second spelling, 2400, used when it marks the end of a day rather than the start. The full rules, with a converter, are on the military time chart page.